Slush pump piston rod assembly



Oct. 31, 1950 H. B. YOUNG 2,528,104

SSSSSSSSSSSSSSSSSSSS SEMBLY HENRY B- YOUNG INVENTOR. BY M 5. W

ATTORNEYS Patented Oct. 31 E50 SLUSH PUMP PISTON ROD ASSEMBLY Henry B. Young, Houston, Tex, assignor to Mission Manufacturing Company, Houston, Tex., a

corporation of Texas Application June 2, 1947,8erial No. 751,701

- 2 Claims. 3

This invention relates to a pump piston and has for an object to provide an improved piston, particularly of the slush pump type, which is to be employed in high pressure pumps handling more or less abrasive material, without danger of leakage, particularly between the piston and the piston rod.

An object of the invention is to provide a substantially leak-proof connection and seal between the piston and the piston rod of a high pressure slush pump.

Many attempts have been made to solve the problem of leakage between the piston and piston rod of high pressure slush pumps, but frequent washouts occur with conventional q ipment, and it is an object of this invention to obviate these washouts.

A further object of this invention is to provide a leakage eliminating means of sealing the piston to the piston rod of a high pressure slush pump or similar pump.

Other and further objects of this invention will be readily apparent when the following description is considered in connection with what is hereinafter claimed and the accompanying drawing wherein;

Fig. 1 a sectional view of a piston and piston rod showing one form of this invention.

Figs. 2, 3 and 4 are similar but fragmentary views each of different forms of this invention.

The piston rod i is provided with an annular flange H from which extends a reduced piston receiving cylindrical neck I! connected thereto by an angular face l3, here shown as forming an angle of about 60 for illustrative purposes, but which may be of any suitable angle, even straight or reentrant. The piston M is shown as a one piece piston body I? with a central radial flange it on opposite sides of which there are the conventional packing seals or rubbers ii.

The piston body II is provided with end faces is and 20 complementary to the angular face is of the piston rod flange H, and a rod nut 2!, adapted to be threaded onto the threaded end 22 of the piston rod neck i2, has an angular face 23 complementary to the piston body face 20. A cylindrical bore 24 extends through the piston body H of such diameter as to have a fairly snug fit on the piston rod neck l2. The description thus far applies equally to each of the different illustrated forms of this invention.

The essence of this invention is in providing a leak proof seal between the piston body I! and piston rod neck i2, that is, to prevent seepage between the piston rod neck 82 and the piston in Fig. 1, an annular recess 26 is provided in end faces i8 and 20 of the piston body l1, and placed in each annular recess 26 is an O-ring 21, of suitable material, such as natural or synthetic rubber or of other suitable plastic material. As will be apparent, this O-ring 21 of suitable shape in cross-section has its annulus diameter somewhat larger than the depth of the recess 26, so that when finally assembled and tightened down, it will be somewhat compresed and thus form a tight and sealing fit between the piston body end faces l3 and 20 and the angular faces l3 and 23 on the piston rod flange I l and rod nut 2|. As will also be apparent, the O-ring and recess at the nut end could be omitted, and the seal at the angular face it could be alone relied on, but the seals at both ends are preferred so as to provide a symmetrical piston body which could be assembled from either end, and would be better balanced in operation. In assembling, the nut 2| would be sufflciently tightened to press the piston body against the angular face E3 of the piston rod flange II and thus compress the O-rings in the recesses to a sealing fit therein against the end faces.

The essence of this invention is carried out in each of the forms shown in Figs. 2, 3 and 4.

In Fig. 2, the recesses 30 are shown as being located in the angular face 3| of the piston rod flange H and in the angular face 32 of the rod nut 2|, with an O-ring 33 in each of them.

In Fig. 3, but a single recess 40 is provided in the bore 21 of the piston body I! to receive the single O-ring 42.

In Fig. 4, the recesses 50 are located in the angles formed by the piston body angular faces 5| and the bore 24 to receive the O-rings 52.

It will be observed that a symmetrical piston body is provided in each of the forms of this invention, and that while the sealing O-ring and recesses have been shown in one or the other of the contacting surfaces, it could equally well be located in both surfaces or intermediate both sur- 'faces, and if desired, sealing O-rings and recesses of two or more of the forms could be all used in a single form.

While the O-ring is shown as being circular in cross section, it is not necessarily so; but may be rectangular or oblong in cross section, so long as its thickness in the direction of the depth of the recess is greater than such depth of the recesses. so that the O-ring will be compressed somewha as the flnal assembly takes place.

What is claimed is l.- Means for sealing a pump piston on a piston rod to prevent leakage therebetween comprising a piston body and piston rod having complementary contacting surfaces inclined with respect to the axis of said rod, said body having a radial flange thereon, packing rubbers mounted on said body above said surfaces and adjacent said flange, means for applying pressure to hold said surfaces in tight metal-to-metal contact, and compressed sealing ring means countersunk into at least one of each pair of the contacting complementary surfaces between the piston and piston rod to provide a fluid tight seal in combination with said metal seal, said contacting surfaces of said piston rod comprising an angular face connecting an annular flange to a reduced cylindrical neck, the end of said neck being threaded, the body of the piston having a cylindrical bore therethrough connecting angular faces at each end, said pres- 2. A slush pump piston and rod combination comprising an annular piston body, a piston rod opening extending therethru, a beveled face at each end of said body around such opening, an annular groove intermediate the inner and outer edges of each face. a resilient seal ring in each REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PA'I'ENTS Number Name Date 1,612,038 Miller Dec. 28, 1926 2,180,795 Christensen Nov. 21, 1939 2,283,460 Pumphrey .1.... May- 19, 1942 2,332,763- .7 Stewart ,Oct.-,.26, 1943 2,417,887 Schmidt Mar. 25, 1947 2,429,426 Phillips et a1 Oct. 21, 1947 

